When John Denver testified at the Senate in 1985, he was really upset that the lyrics in his song "Rocky Mountain High" were misinterpreted as drug related lyrics by people who had never been to the Rocky Mountains. For him, suppression of society begins with censorship of spoken and written word, as it happened in Nazi Germany, and it mustn't be tolerated in any democratic society. People should be free to choose what content they want them and their children to access to, and artists should be free to express themselves in any way they feel like to.
Thus, although he was strongly against any kind of censorship, he considered that there was a need for the creation of a national panel to review lyrics so that artists wouldn't get banned in vain, since this affected their reputation and work. The panel should only warn the consumer of such content.
Dr. Martin Luther King Jr's I Have A Dream speech was more of an argumentative speech, as well as a speech that was persuading the listener to understand.
